Outlet works for two prong plugs but not for three prongs.

Reply Thu 21 Sep, 2017 05:16 pm
Hi, I moved into a new place and one two-plug outlet does not work at all for grounded (three prong) plugs but does work for ungrounded (two prong) plugs as long as no three prong plug is plugged in at the same time. My three light circuit tester shows normal as long as no three-prong plug is in the 2nd plug, but switches to hot ground reversed as soon as any three-prong plug is inserted. Can you tell me the likely problem? Thanks.
  • Topic Stats
  • Top Replies
  • Link to this Topic
Type: Question • Score: 1 • Views: 2,363 • Replies: 3
No top replies

Reply Wed 4 Oct, 2017 01:29 pm
Might be there is a problem in the third prong on your outlet.
0 Replies
Reply Thu 5 Oct, 2017 07:11 pm
Probably you have "back feeding".

This is common, and it happens mostly -as an example- when some receptacles run the same circuits with lights.

You remove the receptacle from the wiring, and you have lights Off. The hot wire will be hot, the neutral will be neutral and ground will be ground.

As soon as you turn the light On, not always but it happens, the hot wire will be always hot, but the neutral wire can give you hot signal as well, and possibly the ground will do the same if somewhere in the circuit the ground and neutral are touching one to another. This happens because the loose wires you are testing are the last end and neutral and ground wires are not returning power back to grounding.

Back feeding is a huge problem when electric power is not disconnected properly.

For example, you have the main panel with two hot phases, neutral and ground wiring. You have lots of devices connected in the house receptacles.

If you disconnect the main ground wire first at the main panel, then the phases of the hot wiring will automatically travel thru the neutral wire and will cause a 220 v circuit in the 110v circuits.

Then, TVs, radios, computers, etc will be burn out because the higher voltage.

In your case, you better pull out the compromised receptacles, check if they are wired properly. You might need to pull more receptacles.

You must use a different kind of tester, with continuity.

Well, I think you might have an idea how to test that circuit following this video.

Reply Sun 15 Oct, 2017 02:57 am
Thanks for your generous help friend. Sorry for late reply.
0 Replies

Related Topics

Main Breaker Tripped 2x - Question by decadent
240 Why - Question by lenchase
Electrical Wiring Question - Question by cdime
electrical showers - Question by grains93
6000W cooktop circuit - Question by 1hairycanary
Tempory power supply - Question by 51 nelson
  1. Forums
  2. » Outlet works for two prong plugs but not for three prongs.
Copyright © 2023 MadLab, LLC :: Terms of Service :: Privacy Policy :: Page generated in 0.03 seconds on 03/24/2023 at 02:41:52